Organic electro luminescent display and manufacturing method thereof

ABSTRACT

An organic light emitting diode includes a lower substrate, luminous element provided with upper and lower electrodes and disposed on the lower substrate, a shielding layer disposed on the luminous clement for shielding outer moisture, the shielding layer being formed of at least one layer, and an upper substrate disposed on the shielding layer.

BACKGROUND OF THE INVENTION

[0001] (a) Field of the Invention

[0002] The present invention relates to an organic light emitting diodeand, more particularly, to an organic light emitting diode that isdesigned being protected from moisture by being encapsulated, therebyimproving luminous efficiency and life span.

[0003] (b) Description of Prior Art

[0004] Generally, an organic light emitting diode is a luminous elementthat emits light by an electron and an electron hole that aredisappeared after being paired with each other when an electric chargeis diffused on an organic electric field luminous layer provided betweenan electron hole diffusing electrode (a positive electrode) and anelectron diffusing electrode (a negative electrode). Such an organiclight emitting diode has an advantaged of being driven at a voltagelower than that required for driving an inorganic light emitting diodeor a plasma display panel (PDP) by 10V.

[0005] In addition, since the organic light emitting diode is thin,light, and good in a sense of color, it has lately attractedconsiderable attention as a next generation flat display. The organiclight emitting diode may be formed of a flexible substrate such as aplastic film.

[0006] However, since the organic light emitting diode cannot standmoisture and oxygen, its luminous efficiency and life span are steeplydeteriorated when it is exposed to the air or outer moisture isinfiltrated in the display. Accordingly, to protect the display from themoisture and oxygen, a metal plate such as a stainless steel is disposedon the organic light emitting diode through a well-known encapsulationprocess to prevent the display from directly exposed to the air.

[0007] In the encapsulation process, the metal plate and the organiclight emitting diode are attached to each other by an adhesive or a UVhardening agent. However, this has a limitation in maintaining theproperty of the organic light emitting diode as the sealing effectcannot be sufficiently obtained at the attaching portion. Further more,the process is complicated.

SUMMARY OF THE INVENTION

[0008] Therefore, the present invention has been made in an effort tosolve the above-described problems of the prior art. It is an objectiveof the present invention to provided an organic light emitting diodethat has an encapsulation structure protecting organic matter and anelectrode from outer moisture, thereby improving luminous efficiency ofthe diode and increasing life span.

[0009] It is another objective of the present invention to provide amethod for processing an encapsulation structure of an organic lightemitting diode, which can prevent the luminous efficiency and life spanof the diode from deteriorating.

[0010] To achieve the above objectives, the present invention providesan organic light emitting diode comprising a lower substrate, a luminouselement provided with upper and lower electrodes and disposed on thelower substrate, a shielding layer disposed on the luminous element forshielding outer moisture, the shielding layer being formed of at leastone layer, and an upper substrate disposed on the shielding layer.

[0011] According to another aspect, the present invention provides amethod for manufacturing an organic light emitting diode, comprising thesteps of disposing a shielding layer on an upper electrode of a luminouselement, exposing an image signal input pad terminal to an luminousupper and lower electrodes through a light exposing and developingprocess, depositing a UV hardening resin on a portion where an end of ashielding layer contacts the upper and lower electrodes of the luminouselement, attaching an upper substrate to a lower substrate, andhardening the UV hardening resin.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a sectional view of an organic light emitting diodeaccording to a first embodiment of the present invention;

[0013]FIG. 2 is a sectional view of an organic light emitting diodeaccording to a second embodiment of the present invention;

[0014]FIG. 3 is a flowchart illustrating a method for manufacturing anorganic light emitting diode according to a first embodiment of thepresent invention;

[0015]FIG. 4 is a sectional view of an organic light emitting diodeaccording to a third embodiment of the present invention;

[0016]FIG. 5 is a sectional view of an organic light emitting diodeaccording to a fourth embodiment of the present invention;

[0017]FIG. 6 is a sectional view of an organic light emitting diodeaccording to a fifth embodiment of the present invention;

[0018]FIG. 7 is a sectional view of an organic light emitting diodeaccording to a sixth embodiment of the present invention;

[0019]FIG. 8 is a sectional view of an organic light emitting diodeaccording to a seventh embodiment of the present invention;

[0020]FIG. 9 is a sectional view of an organic light emitting diodeaccording to an eighth embodiment of the present invention;

[0021]FIG. 10 is a flowchart illustrating a method for manufacturing anorganic light emitting diode according to a second embodiment of thepresent invention; and

[0022]FIG. 11 is a flowchart illustrating a method for manufacturing anorganic light emitting diode according to a third embodiment of thepresent invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0023] The present invention will be described more in detailhereinafter in conjunction with the accompanying drawings.

[0024]FIG. 1 shows an organic light emitting diode according to a firstembodiment of the present invention. The inventive diode comprises lowerand upper substrates 1 and 13 and an element 5 having lower and upperelectrodes 3 and 7, the luminous element 5 being disposed between thelower and upper substrates 1 and 13.

[0025] Attached on the luminous element 5 having the positive andnegative electrodes 3 and 7 is a shielding layer formed by laminating aphotosensitive dry film (9, hereinafter referred as “dry film resist”).The shielding layer formed of the dry film resist 9 can be laminatedwith more than one layer.

[0026] The laminating of the shielding layer after the luminous elementis formed is conducted under a pressure of 1-10⁻⁴ torr, and a moisturerate of 1000-0.1 ppm.

[0027] The luminous element 5 is disposed between the lower and uppersubstrates 1 and 13. An antireflection coating layer 19 is formed underthe upper substrate 13. A UV hardening resin 15 is deposited on an endof the dry film resist 9 and a portion where the upper and lowerelectrodes 1 and 13 of the luminous element 5 contact each other.

[0028] Although the antireflection coating layer 19 disposed under theupper substrate 13, the present invention is not limited to this. Thatis, the dry film resist 9 may be designed functioning as theantireflection layer by itself. Alternatively, the antireflectioncoating layer 19 may be disposed on an upper or lower surface of the dryfilm resist 9.

[0029]FIG. 2 shows an organic light emitting diode according to a secondembodiment of the present invention. In this embodiment, a protectinglayer 17 for shielding moisture and oxygen is further provided under theshielding layer formed of the dry film resist 9.

[0030] The protecting layer 17 can be selected from the group consistingof a transparent inorganic layer, a transparent organic layer and asemitransparent metal layer. The protecting layer 17 may be formed in asingle layer or a multi-layer selected from the group consisting of aninorganic/inorganic layer, an inorganic/organic layer, and anorganic/organic layer.

[0031] In the first embodiment, although the dry film resist 9 islaminated on the luminous element 5 to form the shielding layer, in thisembodiment, the shielding layer may be formed by depositing and drying atransparent photosensitive agent on the luminous element 5. Theshielding layer is protected by a substrate deposited with anantireflection layer and disposed on the luminous element 5.

[0032] A method for manufacturing the above-described organic lightemitting diode will be described hereinafter.

[0033] First, after the organic luminous element is manufacture (S1),the shielding layer is formed by laminating the dry film resist on theupper electrode where the organic luminous element will be disposed ordepositing and drying the transparent photosensitive agent on theorganic luminous element (S3). Then, a light exposure process isperformed to expose a pad end for inputting image signal to the upperand lower electrodes (S5). After a developing process (S6), a portion ofthe electrode for the pad is exposed and dried (S7). Next, the UVhardening resin is deposited on the end of the dry film and a portionwhere the upper and lower electrodes contact each other (S9), afterwhich the upper substrate on which the antireflection film is disposedon the shielding layer formed of the dry film resist and bonded with thelower substrate (S11). Next, the UV hardening resin is hardened by meansof a UV lamp (S13), after which the upper and lower substrates are cutin a predetermined shape by means of a glass cutter (S15) and sealant isdeposited on an end of the upper substrate (S17) so as to dually protectthe display from outer moisture.

[0034] The laminating of the shielding layer after the luminous elementis formed is conducted under a pressure of 1-10⁻⁴ torr and a moisturerate of 1000 ppm-0.1 ppm.

[0035] At this point, the light transmissivity of the dry film resistcan be in a range selected from the group consisting of 0-50%, 50-80%and 80-98%.

[0036] In addition, the dry film resist may be colored or colorless.

[0037] Since the light exposure process for forming the dry film resistand the light exposure process of the UV hardening agent to attach theupper and lower substrates each other are both conducted on the dry filmresist or the upper substrate, the element may be damaged by ultravioletrays. To prevent this, it is preferable to use a colored dry film resisthaving a light transmissivity less than 80%, preferably 50%.

[0038] However, when the upper electrode is formed of a transparentmaterial, the colored dry film resist having a low light transmissivitymay deteriorate the luminous efficiency. At this point, it is preferableto use a material having the light transmissivity above 80%. Inaddition, to minimize the damage of the element by the ultraviolet rays,a material capable of shielding the ultraviolet rays is more preferable.

[0039] In addition, a refractive index of the dry film resist isdesigned having a range selective from the group consisting of 1.2-1.5,1.5-2.0, and 2.0-3.0.

[0040] To add an antireflection function to the dry film resist, the dryfilm resist should be designed having a different reflection index fromthe upper substrate. At this point, when the upper substrate is formedof a glass, the dry film resist is formed having a refraction index of1.2-1.5 or 2.0-3.0 which differs from that of a normal glass. However,when the upper substrate is not glass or is provided with a transparentprotecting layer formed on an upper or lower surface of the substrate ora lower surface of the dry film resist, the refraction index of the dryfilm resist may be in a range of 1.5-2.0 depending on the refractionindexes of the layers.

[0041]FIG. 4 shows an organic light emitting diode according to a thirdembodiment of the present invention. A luminous element 5 provided withelectrodes 3 and 7 is disposed on a lower substrate 1 and a shieldinglayer 9 is disposed on the luminous element 5. A protecting layer 17 isdisposed on the shielding layer 9. An antireflection coating layer 19 isformed on the protecting layer 17. This embodiment is identical to thefirst embodiment except that the upper substrate disclosed in the firstembodiment is omitted. By omitting the upper substrate, themanufacturing process may be more simplified and the manufacturing costas well as the thickness and weight can be reduced.

[0042] In this third embodiment, although the protecting layer 17 isdisposed on the shielding layer 9, the protecting layer 17 as well asthe antireflection coating layer 19 may be omitted to make the displaysimple.

[0043]FIG. 5 shows an organic light emitting diode according to a fourthembodiment of the present invention. A luminous element 5 provided withelectrodes 3 and 7 is disposed on a lower substrate 1 and a protectinglayer 17 is disposed on the luminous element 5. A shielding layer 9 isdisposed on the protecting layer 17. While the shielding layer 9 in thethird embodiment is disposed on the luminous element 5, the shieldinglayer 9 in the fourth embodiment is disposed on the protecting layer 17disposed on the luminous element 5. That is, this embodiment shows thatthe display can be designed in a various disposition. In addition, anantireflection coating layer 19 is disposed on the shielding layer 9.

[0044] Since the shielding layer 9 and the protecting layer 17 in thethird and fourth embodiments are identically designed to those in thefirst and second embodiments, the detailed description thereof will beomitted herein.

[0045] In the third and fourth embodiment, it is preferable that theshielding layer 9 is formed of more than one layer. That is, theshielding layer 9 can be formed of a single layer or a multi-layer.

[0046] In the third and fourth embodiments, the protecting layer 17 isprovided to further enhance the protection effect of the moisture thatmay be introduced into the luminous element 5. Particularly, when theprotecting layer 17 is disposed as the uppermost layer, it can also havea function for preventing the shielding layer 17 from be damaged. Theprotecting layer 17 is identical to that in the first and secondembodiments, the detailed description of which will be omitted herein.However, in the third and fourth embodiments, it is preferable that theprotecting layer 17 has a thickness of 0.01-300 μm.

[0047] Particularly, in the third and fourth embodiments, when theprotecting layer 17 is provided with the upper substrate omitted, thereis an advantage of designing a new optical layer where the frontemission of the display is realized upward.

[0048] A method for manufacturing the organic light emitting diodedescribed in the third and fourth embodiments will be described indetail in conjunction with FIGS. 10 and 10.

[0049] After the lower substrate 1 is first prepared, the luminouselement 5 is manufactured (S31). The luminous element 5 is provided withupper and lower electrodes and attached on the lower substrate 1. Theshielding layer 9 is bonded on the electrode 7 disposed on the element5. The shielding layer 9 is formed in a same manner described inconnection with the first and second embodiments.

[0050] Then, the shielding layer 9 is exposed to the light (S35) anddeveloped (S37), and then the protecting layer 17 is deposed (S39). Ifrequired, the antireflection coating layer 19 may be formed on theprotecting layer 17.

[0051]FIG. 11 shows a flowchart illustrating another example for formingthe protecting layer 9 described in the third and fourth embodiments.That is, the method for forming the shielding layer is different fromthat of the third embodiment. The shielding layer 9 is bonded on theupper electrode and exposed to the light, after which it goes through asand blast process and is hardened.

[0052] That is, after the luminous element is first manufactured (S51),the shielding layer 9 is bonded on the upper electrode (S53). Then, theshielding layer 9 is exposed to the light (S55), after which it goesthrough a sand blast process (S57) and is hardened (S59). The protectinglayer 17 is deposited on the shielding layer 9 (S61).

[0053] The protecting layer 17 described in the third and fourthembodiments can be formed of at least one layer selected from the groupconsisting of an inorganic layer, an organic layer and a metal layer.The protecting layer 17 may be designed to function as an antireflectioncoating layer.

[0054] Preferably, the protecting layer 17 is designed having atransmissivity of a range selected from the group consisting of 0-50%,50-80% and 80-98%. This means that the display can be variously designeddepending on the give conditions.

[0055] The protecting layer 17 may be colored or colorless and designedhaving a refraction index of a range selected from the group consistingof 1.2-1.5, 1.5-20 and 2.0-30.

[0056] By omitting the upper substrate in the third and fourthembodiments, the display has a simple structure and the manufacturingprocess thereof can be more simplified, while obtaining the identicaleffect to those of the first and second embodiments.

[0057] FIGS. 6 to 9 shows fifth to eighth embodiments of the presentinvention, respectively. In these embodiments, to further enhance theencapsulation effect, the shielding layer 9 on the protecting layer 17are formed on the luminous element 5 in a multi-layer structure.

[0058] That is, in the fifth embodiment depicted in FIG. 6, a luminouselement 5 provided with electrodes 3 and 7 is disposed on a lowersubstrate 1 and a first shielding layer 9 for shielding the moisture isdisposed on the luminous element 5. A protecting layer 17 is disposed onthe shielding layer 9 and a second shielding layer 9 is further disposedon the protecting layer 17.

[0059] In the sixth embodiment depicted in FIG. 7, a luminous element 5provided with electrodes 3 and 7 is disposed on a lower substrate 1 anda first protecting layer 17 is disposed on the luminous element 5. Ashielding layer 9 for shielding the moisture is disposed on the firstprotecting layer 17. A second protecting layer 17 is further disposed onthe shielding layer 9.

[0060] In the seventh embodiment depicted in FIG. 8, a luminous element5 provided with electrodes 3 and 7 is disposed on a lower substrate 1and a first protecting layer 17 is disposed on the luminous element 5. Afirst shielding layer 9 for shielding the moisture is disposed on thefirst protecting layer 17. A second protecting layer 17 is furtherdisposed on the shielding layer 9 and a second shielding layer 9 isfurther disposed on the protecting layer 17.

[0061] In the eighth embodiment depicted in FIG. 9, a luminous element 5provided with electrodes 3 and 7 is disposed on a lower substrate 1 anda first protecting layer 17 is disposed on the luminous element 5. Afirst shielding layer 9 for shielding the moisture is disposed on thefirst protecting layer 17. A second protecting layer 17 is furtherdisposed on the shielding layer 9 and a second shielding layer 9 isfurther disposed on the protecting layer 17. A third protecting layer 17is further disposed on the second shielding layer 9.

[0062] In the fifth to eighth embodiments, since shielding layer 9 andthe protecting layer are identical to those of the above embodiments,the description thereof will be omitted herein.

[0063] The fifth to eighth embodiments further enhances theencapsulation effect of the luminous element 5.

[0064] As described above, the present invention provides a laminatingstructure of the dry film resist or a technology for depositing atransparent photosensitive agent on the luminous element, therebyimproving luminous efficiency of the display and increasing life span.

[0065] In addition, the present invention provides a manufacturingprocess simplified while providing a simple structure reducing thethickness and weight of the display.

What is claimed is:
 1. An organic light emitting diode comprising: alower substrate; a luminous element provided with upper and lowerelectrodes and disposed on the lower substrate; a shielding layerdisposed on the luminous element for shielding outer moisture, theshielding layer being formed of at least one layer; and an uppersubstrate disposed on the shielding layer.
 2. An organic light emittingdiode comprising: a lower substrate; a luminous element provided withupper and lower electrodes and disposed on the lower substrate; and ashielding layer disposed on the luminous element for shielding outermoisture, the shielding layer being formed of at least one layer.
 3. Anorganic light emitting diode comprising: a lower substrate; a luminouselement provided with upper and lower electrodes and disposed on thelower substrate; a first shielding layer disposed on the luminouselement for shielding outer moisture, the shielding layer being formedof at least one layer; a protecting layer disposed on the shieldinglayer; and a second shielding layer disposed on the protecting layer. 4.An organic light emitting diode comprising: a lower substrate; aluminous element provided with upper and lower electrodes and disposedon the lower substrate; a first protecting layer disposed on theluminous element; a shielding layer disposed on the first protectinglayer for shielding outer moisture, the shielding layer being formed ofat least one layer; and a second protecting layer disposed on theshielding layer.
 5. An organic light emitting diode comprising: a lowersubstrate; a luminous element provided with upper and lower electrodesand disposed on the lower substrate; a first protecting layer disposedon the luminous element; a first shielding layer disposed on theluminous element for shielding outer moisture, the shielding layer beingformed of at least one layer; and a second protecting layer disposed onthe first shielding layer; and a second shielding layer disposed on thesecond protecting layer.
 5. An organic light emitting diode comprising:a lower substrate; a luminous element provided with upper and lowerelectrodes and disposed on the lower substrate; a first protecting layerdisposed on the luminous element; a first shielding layer disposed onthe luminous element for shielding outer moisture, the shielding layerbeing formed of at least one layer; a second protecting layer disposedon the first shielding layer; and a second shielding layer disposed onthe second protecting layer.
 6. An organic light emitting diodecomprising a lower substrate; a luminous element provided with upper andlower electrodes and disposed on the lower substrate; a first protectinglayer disposed on the luminous element; a first shielding layer disposedon the luminous element for shielding outer moisture, the shieldinglayer being formed of at least one layer; a second protecting layerdisposed on the first shielding layer; a second shielding layer disposedon the second protecting layer; and a third protecting layer disposed onthe second shielding layer.
 7. An organic light emitting diode of one ofclaims 1 to 6 wherein the shielding layer disposed on the luminouselement is formed of a dry film resist laminated on the luminouselement.
 8. An organic light emitting diode of one of claims 1 to 6wherein the shielding layer disposed on the luminous element is formedby depositing a transparent photosensitive agent on the luminous elementand drying the deposited agent.
 9. An organic light emitting diode orclaim 1 wherein the upper substrate is provided at its bottom surfacewith an antireflection coating layer.
 10. An organic light emittingdiode of one of claims 1 to 6 wherein the shielding layer is formed ofan antireflection layer.
 11. An organic light emitting diode of claim 1wherein the shielding layer is provided with a protecting layer selectedfrom the group consisting of an inorganic layer, an organic layer and asemi-transparent metal layer.
 12. An organic light emitting diode ofclaim 2 wherein the shielding layer is provided at its upper or lowersurface with a protecting layer selected from the group consisting of aninorganic layer, an organic layer and a semi-transparent metal layer.13. An organic light emitting diode of one of claims 3 to 6 and claims11 and 12 wherein the protecting layer is provided at its upper or lowersurface with an antireflection coating layer.
 14. An organic lightemitting diode of one of claims 1 to 6 and claims 11 and 12 wherein theprotecting layer is formed of a multi-layer selected from the groupconsisting of an inorganic/inorganic layer, an inorganic/organic layer,and an organic/organic layer.
 15. An organic light emitting diode ofclaim 1 wherein a UV hardening resin is deposited on a portion where anend of the shielding layer contacts the upper and lower electrodes ofthe luminous element.
 16. An organic light emitting diode of one ofclaims 1 to 6 and claims 11 and 12 wherein the protecting layer disposedon the shielding layer is a metal layer.
 17. An organic light emittingdiode of claim 1 wherein the upper and lower substrates are formed of aglass or a synthetic resin film.
 18. An organic light emitting diode ofclaim 7 wherein a transmissivity of the dry film resist is in a range of0-50%.
 19. An organic light emitting diode of claim 7 wherein atransmissivity of the dry film resist is in a range of 50-80%.
 20. Anorganic light emitting diode of claim 7 wherein a transmissivity of thedry film resist is in a range of 80-98%.
 21. An organic light emittingdiode of claim 7 wherein the dry film resist is colored or colorless.22. An organic light emitting diode of claim 7 wherein a refractionindex of the dry film resist is in a range of 1.2-1.5.
 23. An organiclight emitting diode of claim 7 wherein a refraction index of the dryfilm resist is in a range of 1.5-2.0.
 24. An organic light emittingdiode of claim 7 wherein a refraction index of the dry film resist is ina range of 2.0-3.0.
 25. An organic light emitting diode of claim 7wherein a thickness of the dry film resist is in a range of 2-300 μm.26. An organic light emitting diode of one of claims 3 to 6 and claims11 and 12 wherein a transmissivity of any one of the protecting layer isin a range of 0-50%.
 27. An organic light emitting diode of one ofclaims 3 to 6 and claims 11 and 12 wherein a transmissivity of any oneof the protecting layers is in a range of 50-80%.
 28. An organic lightemitting diode of one of claims 3 to 6 and claims 11 and 12 wherein atransmissivity of any one of the protecting layers is in a range of80-98%.
 29. An organic light emitting diode of one of claims 3 to 6 andclaims 11 and 12 wherein any one of the protecting layers is colored orcolorless.
 30. An organic light emitting diode of one of claims 3 to 6and claims 11 and 12 wherein a reflection index of any one of theprotecting layers is in a range of 1.2-1.5.
 31. An organic lightemitting diode of one of claims 3 to 6 and claims 11 and 12 wherein areflection index of any one of the protecting layers is in a range of1.5-2.0.
 32. An organic light emitting diode of one of claims 3 to 6 andclaims 11 and 12 wherein a reflection index of any one of the protectinglayers is in a range of 2.0-3.0.
 33. An organic light emitting diode ofone of claims 3 to 6 and claims 11 and 12 wherein a thickness of any oneof the protecting layers is in a range of 0.01-300 μm.
 34. An organiclight emitting diode of one of claims 2 to 6 wherein the lower substrateis formed of a glass or a plastic film.
 35. A method for manufacturingan organic light emitting diode, comprising the steps of: disposing ashielding layer on an upper electrode of a luminous element; exposing animage signal input pad terminal to luminous upper and lower electrodesthrough a light exposing and developing process; depositing a UVhardening resin on a portion where an end or a shielding layer contactsthe upper and lower electrodes of the luminous element; attaching anupper substrate to a lower substrate; and hardening the UV hardeningresin.
 36. A method for manufacturing an organic light emitting diode,comprising the steps of: disposing a shielding layer on an upperelectrode of a luminous element; and exposing an image signal input padterminal to luminous upper and lower electrodes through a light exposingand developing process.
 37. A method for manufacturing an organic lightemitting diode, comprising the steps of: disposing a shielding layer onan upper electrode of a luminous element; exposing an image signal inputpad terminal to an luminous upper and lower electrodes through a lightexposing process and removing a portion of the shielding layer on thepad terminal through a sand blasting process; and hardening theshielding layer.
 38. A method of any one of claims 35, 36 and 37 whereinthe shielding layer is laminated on the luminous element under apressure of 1-10⁻⁴ torr and a moisture rate of 1000 ppm-0.1 ppm.
 39. Amethod of claim 35 further comprising the step of, after the hardeningstep, sealing ends of the upper and lower substrates using sealant. 40.A method of claim 35 further comprising the step of, after the exposingstep, deposing a protecting layer on the shielding layer.
 41. A methodof claim 37 further comprising the step of, after the hardening step,deposing a protecting layer on the shielding layer.